Sets and Operations with Them

4

Correct

This is correct! Indeed, the repetitions in the list of elements does not matter, we need only to count the number of distinct elements in the list.

$B = \{1, 7, 11\}$

Correct

Correct! All elements of $B$ belong to $A$ .

$B = \{1, 3, 4, 8\}$

$B=\emptyset$

Correct

Correct! There are no elements in $B$ , so indeed every element of $B$ is contained in $A$ .

$B = \{1, 3, 4, 7, 10, 11\}$

Correct

Correct! All elements of $B$ belong to $A$ .

$B = \{1, 3, 4, 5, 7, 10, 11\}$

$A \cap B = \{1, 3, 5, 7\}$

$A \cap B = \{1, 2, 5\}$

$A \cap B = \{1, 2, 3, 4, 5, 6, 7\}$

$A \cap B = \{2, 5\}$

Correct

This is correct! Intersection is the set of all elements that belong both to $A$ and $B$ .

$A \cup B = \{1, 3, 5, 7\}$

$A \cup B = \{1, 2, 5\}$

$A \cup B = \{1, 2, 3, 4, 5, 6, 7\}$

$A \cup B = \{1, 2, 4, 5, 7\}$

Correct

This is correct! Union is the set of all elements that belong to at least one of the sets $A$ and $B$ .